Gaseous electric discharge device



1934- cs. GA'IDIES ET AL 1,968,822

GASEOUS ELECTRIC DISCHARGE DEVECE OriginaLFiled Jan. '7, 1932 INVENTORS ATTORNEY UNITED STATES PATENT OFFICE 1,968,822 GASEOUS ELECTRIC msomaon navrcu Georg Gaidiea, Berlin-Pankow, and Martin Roger, Berlin, Germany, assignors to General Electric Company, a corporation of New York Application January 7, 1932, Serial No. 585,348. Renewed October 24, 1933; In Germany January 17, 1931 7 Claims. (01. 176-122) The present invention relates to gaseous elecno appreciable blackening or the walls of the tric discharge devices generally and more parcontainer even after an operating life of several ticularly the invention relates to such devices in thousand hours. This discovery makes available which a metal vapor is used as the entire gaseous foruse in the arts generally and for the first time content or as a component of the gaseous content. the intense green light emitted by magnesium 60 The object of the invention is to provide an vapor when excitedtoluminescence by an electric electric discharge device the gaseous content of discharge. Magnesium vapor is also rich in 111-, which consists wholly, or in part of magnesium tra-violet radiations and an electric discharge I metal vapor. Another object of the invention is device having a filling of magnesium vapor is a m to provide such a device of great efficiency and very efflcient' ultra-violetgenerator. 5 havingalong operating life. A further object of In the drawing accompanying and for i g the invention is'to provide a magnesium vapor part of this specification an embodiment of the filled electric discharge device useful as a lamp invention is shown in a sectional side elevational and as an ultra-violet generator. Still further' View 7 r objects and advantages attaching to the device Referring to the drawing the new and novel and to its use and operation will be apparent to gaseous electric discharge device comprises a those skilled in the art from the following pardouble-walled container '7, 8 having electrodes 5 ticular description. and 6 sealed therein at each end thereof. Said It is well known in the, art that a gaseous eleccontainer has a, filling consisting wholly of magtrio discharge device having a filling of alkali nesium vapor or ofamixture of magnesium vapor metal vapor and particularly sodium and cadmiand a starting gas, such as for example, a rare um vapor is a very efiicient light source; howgas as argon, krypton, xenon, etc. Inner wall ever, it is also well known in the art that a con- 'I of said container '7, 8 is made of the loom-silitainer for Such a d vi e ma e t e cus omary cate glass such as that, for example, disclosed comm r ial lasses becomes blackened after a in co-pending application, Serial No. 470,436, short period of operation due to the chemical ac filed July 24, 1930 and being the invention of tion of the alkali metal vapor on the glass walls Georg Gaidies and Marcello Pirani, and t of the containenthis being true even with a outer wall 8 is made of the usual commercial quartz container. -p ndi appl at lasses. This structure is advisable since the 3 al N 7 y 9 0, b i g the inboro-silicate glass is slightly hygroscopic. I have 85 vention of Georg Gaidies and Marcello Pirani, 9. found that the born-silicate glass composing glass i disclosed w h is h mically stable in inner wall 7 transmits ultra-violet radiations satthe pr of alkali m l v p n particuisfactorily if it is used in a very thin sheet, thereularly sodium vaponand in co-pending applicafore when it is desired to use a magnesium vapor tion, SerialNO- 510,22lfl1ed January 3 filled electric discharge device asan ultra-violet 90 inc e nvent o o Marce Pirani, Martin generator it is advisable that inner wall 7 should e r nd e rg G di s. a lass i disclosed wh h not exceed 0.3 mm. in thickness, and outer wall is chemically stable in the presence of alkali '7' should, of course, be made of a glass whic .m V p and particularly Cadmium p transmits ultra-violet radiations such as quartz such glasses being bo icateglasses containor Uviol glass. Outer wall 8 is necessary in this ing not more than silici aci id s a coninstance to give structural strength to the considerable share of boric acid and the usual glass tam r 7, 3 a a container consisting of a thin forms, or bases such as'alkalies,,alkali earths and glass is dimcult to make andis structurally weakaluminium oxide. It has hi h r o n h u ht The boro-silicate glass of inner wall 7 is applied impossible to use a container made of such glasses in thi coating t th t m n of t ing of magnesium vapor due to the necessary Electrodes 5 and 6 are si'ntered, mixed oxide and alkali content of such glasses and due to the fact metal electrodes such as those dfmclcsed in 00- that magnesium vapor is so active chemically that pending applications, Serial No. emcee, filed July 50 it has been used to separate alkali metals from 9, 1929, being the invention of. Marcello Pirani 105' their oxides. *We have discovered and demonand Hans Ewest and Serial No. 447,051, filed strated, however, that such thought is erroneous April 24, 1930, being the invention of Georg and that an electric discharge device having a Gaidies and Marcello Pirani, or any other eleccontainer made of the aforementioned glasses trodes chemically resistant tomagnesium vapor and having a filling of magnesium vapor shows maybe used as desired. V no for an electric discharge devic containing a fill- 'tainer 8 which transmits ultra-violet radiations. 1m

mixed with not more than silicic While we have shown and described a particular embodiment of our invention it will be understood that we contemplate that numerous substitutions, modifications, and changes in the form and details of the device may be made by those skilled in the art without departure from the broad spirit and scope of the invention, for example, the inner wall '7 may be separated from the outer wall 8 by a space and said space may be evacuated to decrease the radiation of heat from said device to prevent the condensation of said magnesium vapor during the operation of the device or said outer container may be of heat absorbing glass for the same purpose or both structures may be used as desired and the inner layer 7 may be fused onto the outer layer 8 as a glaze.

What we claim as new and desire to secure by Letters Patent of the United States, is,-

1. An electric discharge device comprising in combination a container, electrodes sealed therein, a filling of magnesium vapor therein and a surface comprising-a glass consisting of the usual glass bases as alkalies, alkali earths and aluminium oxide mixed with not more than 50% silicic acid interposed between the filling of magnesium vapor and said container.

2. An electric lamp comprising in combination a container, electrodes sealed therein, a filling of magnesium vapor therein and a surface comprising a glass consisting of the usual glass bases as alkalies, alkali earths and aluminium oxide acid interposed between the filling of magnesium vapor and said container.

3. An ultra-violet generator comprising in combination a container, electrodes sealed therein, a filling of magnesium vapor therein and a v surface comprising a glass consisting of the usual glass bases as alkalies, alkali earths and aluminium oxide mixed with not more than 50% silicic acid interposed between the filling of magnesium vapor and said container.

4. An electric discharge device comprising in combination a container, electrodes sealed therein, a filling of magnesium vapor therein and a surface comprising an inert glass interposed between the filling of magnesium vapor and said container.

5. An electric discharge combination a container, electrodes therein, a filling of magnesium vapor therein, the surface of the container exposed to the magnesium vapor comprising a glass made of boric acid, silicic acid, and a suitable base, the silicic acid'being not substantially greater than 50% of the mixture.

6. An electric discharge device comprising a container, electrodes therein, a filling of magnesium vapor therein, the surface of the container exposed to the magnesium vapor comprisdevice comprising in ing a glass made of not to exceed substantially 50% of silicic acid, 30% of boric acid and a suitable glass base such as alkali, alkali earth, and aluminium oxide.

7. An electric discharge device comprising a container, electrodes therein, a filling of magnesium vapor therein, the surface of the container exposed to the magnesium vapor comprising a glass made of from substantially 10 to 26% of silicic acid, substantially|40 to 60% of boric acid,substantially 11 to 13% of aluminium oxide and substantially 14 to 16% of suitable glass constituents such as alkali and. alkali ea'rth.

GEORG GAIDIES. MARTIN REGER. 

